Justification:Acanthurus xanthopterus is widespread in the Indo-Pacific and is common in parts of its range. It is a targeted food fish in parts of its distribution. There are no signs of global population declines through harvesting. Its distribution overlaps with a number of marine protected areas. It is therefore listed as Least Concern. We recommend monitoring of the harvest levels and population trends of this species.

Acanthurus xanthopterus is widespread in the tropical Indo-Pacific from eastern Africa to the Americas. In the Indo-Pacific, it occurs from eastern Africa to the Hawaiian islands and French Polynesia, northwards to southern Japan, and south to the Great Barrier Reef and New Caledonia. In the eastern Pacific, it ranges from the mouth of the Gulf of California to Ecuador, including all the oceanic islands, but excluding the Central American Gap (coastal El Salvador, Guatemala). One record from Halaniyat Islands, southern Oman is possibly a vagrant (J. McIlwain unpub. data).

Acanthurus xanthopterus is common in outer reef slopes. It was recorded as occasional in terms of relative abundance in Milne Bay Province and northern Bismarck Sea, Papua New Guinea. It is usually on sandy slopes adjacent to reefs (Allen 2003, 2009). It is moderately common in Raja Ampat, Indonesia (Allen 2003b). It is uncommon in the American Samoa National Park (National Park of Samoa Checklist of Fishes, accessed 21 April 2010). It is rare in Palawan, Philippines; only a few sub-adults were observed (Werner and Allen 2000, Palawan Council for Sustainable Development unpub. data). It is common elsewhere in the Philippines (B. Stockwell pers. comm. 2010).

In American Samoa, landings of acanthurids totaled 13,431 lbs. or 9% of the total catch. This species and Alogo (Acanthurus lineatus), comprised 82% of the total acanthurid catch. A. xanthopterus were caught by hook and line methods and 79% by weight were caught in the Fagatogo area. Most of those were caught by hand line and rod and reel anglers fishing from small canoes. 5,996 lbs were landed in the study area from July 1990 through June 1991 (Ponwith 1991).

This species comprises 9.5% of the acanthurid fishery in Pohnpei (Rhodes et al. 2008), 5% of the fishery in Guam and 8% in Saipan (Guam Division of Aquatic and Wildlife Resources unpub. data, P. Houk unpub. data). This species is collected as an aquarium fish in West Hawaii. The total number of individuals caught from FY 2005-2009 was 124 with a total value of $321 (Walsh et al. 2010).

In Kenya, landings during 1978-2001 for families that are less important in commercial catches (e.g., scarinae and Acanthuridae) showed rising catches (1978-1984) followed by a general decline during the 1990s (Kaunda-Arara et al. 2003).

In the tropical eastern Pacific, this species can be locally common. According to Robertson and Allen (1996), this fish has a doubtful population status in Clipperton Atoll. It was studied in the Galapagos archipelago, with an overall mean density of 0.06 ind/500 m2 (Edgar et al. 2004). Some surveys conducted in northern part of Costa Rica did not observe this fish (Dominici-Arosemena et al. 2005, Figueroa 2001). However, it was observed three times in one coral zone north of Costa Rica (Espinoza and Salas 2005). It has been regularly recorded in southern Costa Rica, including Cano Island and Cocos Island.

According to Aburto-Oropeza and Balart (2001), A. xanthopterus is a rare species at Los Islotes, Gulf of California, having an occurrence frequency below 10%. A survey conducted at Gorgona Island, Colombia, observed this fish to have a mean recruitment of 0.01+/-0.2 settling individuals with an average size of 23.0+/-0.0 mm (Mora and Zapata 2002). It is abundant at Gorgona and El Slavador, and along much of the continental tropical eastern Pacific coast south of the Gulf of California; moderately common off the offshore tropical eastern Pacific islands and Gulf of California. Densities in the southern part of its continental range are considerably higher than observed at any site surveyed in the Indo-West Pacific.

This reef-associated species lives in various reef habitats, sand slopes and lagoons (Kuiter and Tonozuka 2001). It is more common in lagoons and bays than exposed outer reef areas; usually found at depths greater than 10 to 15 m; reported to 90 m (Randall 2001b). Consistently feeds on the faeces of other pelagic species especially Carangids (J.H. Choat, pers comm. 2010). In Gulf of Chiriqui, Panama, this species can be found over most kinds of substrata except for deep zones of middle size rocks and sand (Dominici-Arosemena and Wolff 2006). According to Rubio (1986), at Gorgona Island, Colombia, this fish (cited as A. glaucopareius) is abundant on rocky and sandy substrata, while it is also frequently found on coralline substrata.

Juveniles recruit to shallow, protected, turbid inshore waters, while adults are usually found in outer reef areas (J.H. Choat pers. comm. 2010). It is also found on outer reef areas (Myers 1991, Kuiter and Tonozuka 2001). It feeds on sediment and detritus (Choat et al. 2004). It is classified as a grazer/detritivore (Choat and Bellwood pers. obs. in Green and Bellwood 2009). It is more inclined than other species of Acanthurus to stray from the shelter of coral reefs or rocky outcrops. It may occur as solitary individuals or in small aggregations (Randall 2001b). Maximum age is 34 years (Choat and Robertson 2002a).

Reproduction

The sexes are separate among the acanthurids (Reeson 1983). Acanthurids do not display obvious sexual dimorphism, males assume courtship colours (J.H. Choat pers. comm. 2010). This species forms spawning aggregations in Palau from January-May during the new and full moon (Johannes,1981). It was also reported to form spawning aggregations on the Great Barrier Reef (Squire and Samoilys unpub.).

Acanthurus xanthopterus is of minor importance in commercial fisheries and in the aquarium trade. In Australia, fishermen are starting to target this species along with A. dussumieri and A. blochii. It is a targeted fish species in Apo Island and elsewhere in the Philippines. It is occasionally found in markets. It is caught by hook and line and spears (A. Candido pers. comm. 2010). It is a component of the aquarium trade (Global Marine Aquarium Database accessed 19 March 2010). Online prices range from $39.99-$69.99 per individual (L. Rocha pers. comm. 2010).

Acanthurus xanthopterus is of minor importance in commercial fisheries and in the aquarium trade. There may be some localized population declines from fishing.

Surgeonfishes show varying degrees of habitat preference and utilization of coral reef habitats, with some species spending the majority of their life stages on coral reef while others primarily utilize seagrass beds, mangroves, algal beds, and /or rocky reefs. The majority of surgeonfishes are exclusively found on coral reef habitat, and of these, approximately 80% are experiencing a greater than 30% loss of coral reef area and degradation of coral reef habitat quality across their distributions. However, more research is needed to understand the long-term effects of coral reef habitat loss and degradation on these species' populations. Widespread coral reef loss and declining habitat conditions are particularly worrying for species that recruit into areas with live coral cover, especially as studies have shown that protection of pristine habitats facilitate the persistence of adult populations in species that have spatially separated adult and juvenile habitats (Comeros-Raynal et al. 2012).

There are no species-specific conservation measures in place for this species. However, its distribution overlaps several marine protected areas within its range. In Queensland, Australia, there is a recreational catch limit of five per species and a minimum size limit of 25 cm (Department of Primary Industries accessed 8 April 2010).